The invention is directed to new benzhydrol derivatives which are distinguished by fungicidal activity, especially against Piricularia oryzae in rice, a process for the production of these compounds, agents containing these compounds as active material, as well as the use of these active materials as a fungicidal agent in the protection of plants.
It is known that di-(p-chlorophenyl)-cyclopropylmethanol has fungicidal activity against Fusarium culmorum, Alternaria Tenuis, Botrytis cianera, and Phytophthora infestans. Basschots, U.S. Pat. No. 3,287,213, the entire disclosure of which is hereby incorporated by reference. However, in using this active material frequently the cultivated plants are influenced disadvantageously.
It has now been found that benzhydrol derivatives of general formula (I): ##STR2## in which R is an ethyl or more preferably a methyl group and R.sub.1 is a halogen or hydrogen atom exhibit an excellent fungicidal activity for the protection of cultivated plants, especially against Piricularia oryzae in rice, without influencing the useful plants disadvantageously through undesirable side effects.
With the active compounds of formula (I) the fungi present on plants and plant parts (fruits, blossoms, foliage, stems, tubers, roots) and related useful cultivated materials are checked or destroyed, in which case even later growing plant parts remain protected from this type of fungi.
The compounds of formula (I) furthermore can be used as a caustic agent for treating seeds (fruits, tubers, grains) and plant cuttings for protection before fungal infections as well as against phytopathogenic fungi occurring in the soil.
Especially outstanding are compounds of general formula (I) in which R.sub.1 is a fluorine or chlorine and R is the methyl group. However, the preferred compound is .alpha.-(1-methyl-cyclopropyl)-4,4'-dichlorobenzhydrol.
Other compounds within formula (I) include
.alpha.-(1-methylcyclopropyl)-4,4'-difluorobenzhydrol, PA1 .alpha.-(1-methylcyclopropyl)-4,4'-dibromobenzhydrol, PA1 .alpha.-(1-ethylcyclopropyl-4,4'-dichlorobenzhydrol, PA1 .alpha.-(1-ethylcyclopropyl)-4,4'-dibromobenzhydrol, PA1 .alpha.-(1-ethylcyclopropyl)-4,4'-difluorobenzhydrol, PA1 .alpha.-(1-methylcyclopropyl)-benzhydrol, and PA1 .alpha.-(1-ethylcyclopropyl)-benzhydrol.
The compounds of the invention can be made from the corresponding halobenzenes or dihalobenzenes and the 1-methyl or 1-ethylcyclopropane-carboxylic acid esters in a known manner by means of a Grignard reaction.
The cyclopropylcarboxylic acid ester starting materials mentioned can be prepared according to the method described in Cannon et al, J. Amer. Chem. Soc. Vol. 81 pages 1660-1666, the entire disclosure of which is hereby incorporated by reference and relied upon.
Unless otherwise indicated all parts and percentages are by weight.
The compositions can comprise, consist essentially of or consist of the stated materials and the processes can comprise, consist essentially of the stated steps with such materials.